Orchard Therapeutics Presents New Interim Data from OTL-203 Proof-of-concept Study for MPS-I

May 15, 2020

Orchard Therapeutics (Nasdaq: ORTX), a global gene therapy leader, today announced new interim data from an ongoing proof-of-concept clinical trial evaluating the safety and efficacy of OTL-203, an ex vivo autologous hematopoietic stem cell (HSC) gene therapy in development for the treatment of mucopolysaccharidosis type I (MPS-I) at the San Raffaele Telethon Institute for Gene Therapy (SR-Tiget) in Milan, Italy. The results are being shared virtually in two presentations at the American Society of Gene & Cell Therapy (ASGCT) 23^rd Annual Meeting, including the main dataset in an invited oral presentation today.

As of April 2020, all eight patients with the severe Hurler subtype of MPS-I have been treated with OTL-203. Patients have been followed for a minimum of three months, with the longest follow-up extending out to 18 months.

Treatment with OTL-203 and the selected conditioning regime were well-tolerated across all eight patients and demonstrated:

• Rapid hematologic reconstitution, with neutrophil and platelet engraftment within 21 days following treatment – achieving a primary outcome measure of hematological engraftment within 45 days of infusion.
• Biological efficacy demonstrated by supranormal IDUA enzyme expression in peripheral blood, with the first two patients treated achieving stable supranormal levels up to 12 months post gene therapy.

Full press release can be found here